class Solution {
public:
    int findPeakElement(vector<int>& nums) {
        int n = nums.size();
        int left = 0, right = n - 1;
        while (left < right) {
            int mid = left + (right - left) / 2;
            if (nums[mid] > nums[mid+1]) right = mid;
            else left = mid + 1;
        }
        return right;
    }
};